Proteins are immobilized to various surfaces for a myriad of purposes, such as in the production of protein “chips” or other analytical tools useful in studying protein-ligand and protein-protein interactions. Devices in which such proteins are immobilized covalently are generally more robust than their non-covalent counterparts.
Typically covalent immobilization has been accomplished through reactions between electrophilic reagents and exposed nucleophilic hydroxyl, amino, carboxylate, and sulfhydryl moieties found in the side chains of naturally occurring amino acids located on the surface of proteins. This approach has two problems. It is difficult to select among the many nucleophiles on the surface of the protein targeted for immobilization and it is difficult to distinguish between those nucleophiles on the protein and those in other biological molecules that may be present in a complex mixture. Thus, it is difficult to target a specific site in a specific protein for covalent attachment.
As such, there exists a need for structures and methods for covalent immobilization of proteins that does not rely upon nucleophilic moieties found in the side chains of naturally occurring amino acids.